The Greek champions lead 2-0 from the first leg two weeks ago and head to the home of the Premier League champions knowing that an away goal will all but seal a place in the quarter-finals.

"We need to score to make sure we make it difficult for them as we know that United have a strong desire to turn the tie around," Michel told reporters on Tuesday.

United's disastrous season plummeted to new lows on Sunday as they were dismantled 3-0 by Liverpool in the Premier League, but while David Moyes's side look a shadow of their former self, Michel is still wary of a famous comeback.

"We aim to do what we always do and that is concentrate on our own game," he added. We know our opponents very well and we know that 2-0 is not a serious advantage."

Javier Saviola could make his 100th European appearance if he plays after missing the first leg through injury and will compete with Nelson Valdez for the lone striking berth, with striker Michael Olaitan absent after his collapse during a league fixture against Panathanaikos.